The specific objectives of this study are to examine the role of dietary sodium reduction with and without potassium chloride supplementation in controlling blood pressure in hypertensive men. Hypertensive men identified with controlled blood pressure, and on antihypertensive medication for at least four years. Eligible men (n=391) have been randomized to one of three groups: Group I (n=156), Dietary Sodium reduction/placebo; Group 2 (n=156), Dietary Sodium reduction, KCL 96 mEq/daily; Group 3 (n=79), a group that continues on antihypertensive medication. After 12 weeks of intervention, antihypertensive medications in Groups 1 and 2 are withdrawn. Medications are then reinstituted if blood pressures go up to hypertensive levels. Major end-points are the proportion of groups 1 and 2 who require reinstitution of medication, the dose and number of medications required to control blood pressure and blood pressure change. This proposal is for two further years of study which will permit each randomized participant to be followed for at least two years. It includes 18 months of clinic visits and 6 months for data processing, analysis and preparation of the major results paper.